Attila Demény

Attila Demény
Research Centre for Astronomy and Earth Sciences · Institute for Geological and Geochemical Research

Prof. Dr.

About

183
Publications
36,237
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3,001
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Additional affiliations
September 1989 - present
Hungarian Academy of Sciences
Position
  • Research Director

Publications

Publications (183)
Article
Full-text available
Alteration of conventional carbonate stable isotopes (δ18O, δ13C) in cave walls has been shown to be a useful tool to identify cave formation driven by deep-seated processes, i.e., hypogene karstification. If combined with a prior information on the paleowater stable isotope composition, further insights can be obtained on the temperature and the s...
Article
Full-text available
Stable isotope-based dietary information on the tenth century CE Hungarian population serves as a valuable comparative tool to other dietary stable isotope studies in the region. This study presents a multiproxy approach involving skeletal samples with the least diagenetic alteration and the best-preserved primary signals. Dental and bone samples c...
Article
A 95 m thick succession of grey siliceous limestone and marl on Mount Rettenstein in the Northern Calcareous Alps allowed us to study well-preserved and diverse radiolarian assemblages across the Sinemurian–Pliensbachian boundary. The distribution of 31 most characteristic radiolarian species is presented. Ammonites of the Jamesoni Subzone, the top...
Article
The aim of the study was to reveal and compare the microbiota of different carbonate speleothems from two different epigenic karst regions (Baradla and Csodabogyós caves) in Hungary. Stalagmites, stalactites, soda straws, moonmilks, cave wall surfaces and dripping waters were sampled and plated on subsurface-environment imitating culture media cont...
Article
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In this study, already published and new monitoring data are compiled from the Baradla and Béke caves in the Aggtelek Karst, from the Vacska Cave in the Pilis Mountains as well as from the Szeml} ohegy and Pálvölgy caves in the Buda Hills. Recent investigations (2019-2020) include monitoring of climato-logical parameters (e.g., temperature, CO 2) m...
Article
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Natural CO2 reservoirs provide an opportunity to study long-term fluid-rock interactions, which are essential to reassure the safety of mineral storage of carbon-dioxide. The Mihályi-Répcelak field (Pannonian Basin, Central Europe) is one of the largest natural CO2-bearing reservoirs in Europe (25 Mt). The CO2 was trapped in Neogene sandstones, whi...
Article
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The first Hungarians settled the Carpathian Basin in the 9th and 10th centuries CE, during the Hungarian Conquest. The 10th century CE Kenézlő-Fazekaszug is one of several cemeteries from this period that exist across present-day Hungary. Although stable isotope studies have investigated the diet of medieval Europeans, this paper details the first...
Article
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Last glacial North Atlantic climate is characterized by abrupt, centennial-millennial scale climate oscillations, called Dansgaard-Oeschger (D-O) events. Understanding the cause and propagation of these D‒O events into Eurasia is hampered by the scarcity of quantitative paleotemperature estimates from continental archives with precise, independent...
Article
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Speleothems (dominated by cave-hosted carbonate deposits) are valuable archives of paleoclimate conditions. As such, they are potential targets of clumped isotope analyses that may yield quantified data about past temperature variations. Clumped isotope analyses of stalagmites, however, seldom provide useful temperature values due to various isotop...
Article
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The Dachstein platform was an extensive carbonate platform developed on the westernmost shelf of the Neotethys during the Late Triassic, now preserved in various tectonic units disrupted during the Alpine orogeny. Despite being the focus of a multitude of sedimentological, paleontological and other studies, the demise of this platform remains contr...
Article
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The combined use of the stable isotope compositions of speleothem carbonate and inclusion-hosted water presents great potential in paleotemperature reconstructions, due to the various temperature-dependent isotope fractionations detected in cave systems and their environment. This paper evaluates the applicational possibilities of hydrogen and oxyg...
Article
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Societal concerns about future hydroclimate changes urge a thorough understanding of the governing processes. Here, an analysis of Middle and Late Holocene speleothem-based hydroclimate reconstructions and paleoclimate model simulations reveals sub-millennial fluctuations in the spatiotemporal variability of precipitation in the European and Medite...
Data
Data supporting Comas-Bru et al., 2020 (ESSD): https://doi.org/10.5194/essd-12-2579-2020
Article
Full-text available
Characterizing the temporal uncertainty in palaeoclimate records is crucial for analysing past climate change, correlating climate events between records, assessing climate periodicities, identifying potential triggers and evaluating climate model simulations. The first global compilation of speleothem isotope records by the SISAL (Speleothem Isoto...
Article
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The end-Triassic extinction is one of the major Phanerozoic mass extinctions and it appears to have been linked to coeval rapid and severe environmental change, thought to be triggered by volcanism in the Central Atlantic Magmatic Province (CAMP). However, direct stratigraphic evidence to substantiate this linkage and help develop scenarios for the...
Article
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One of the most significant cultural transformations in European prehistory occurred in the middle of the 6th millennium BC in the heart of the Carpathian Basin. The northward expansion of Mediterranean farming groups (Starčevo-Körös-Criş cultural complex) halted and underwent a complete transformation giving rise to a new cultural group carrying a...
Article
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Amorphous calcium carbonate (ACC) is a precursor of crystalline calcium carbonates that plays a key role in biomineralization and polymorph evolution. Here, we show that several bacterial strains isolated from a Hungarian cave produce ACC and their extracellular polymeric substance (EPS) shields ACC from crystallization. The findings demonstrate th...
Preprint
Full-text available
Abstract. Characterising the temporal uncertainty in palaeoclimate records is crucial for analysing past climate change, for correlating climate events between records, for assessing climate periodicities, identifying potential triggers, and to evaluate climate model simulations. The first global compilation of speleothem isotope records by the SIS...
Article
Fluids play a crucial role in element mobility and mass transfer at the slab-mantle interface in subduction zones. However, tracing the source and chemical composition of subduction zone fluids still remains challenging. High-pressure (HP) metamorphic leucophyllites, mainly composed of quartz, muscovite/phengite and Mg-chlorite, occur in several lo...
Article
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The Lower Triassic succession of the Transdanubian Range in Hungary comprises limestones, dolomite, marl, sandstones and siltstones, deposited in tidal flat, lagoon and ooid shoal environments on the marginal ramp of the western Neotethys. Seven cores were chosen for petrographic and stable isotope investigations aiming to reconstruct the paragenet...
Article
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The region comprising of East Central Europe, South East Europe and Turkey contributed to the SISAL (Speleothem Isotopes Synthesis and AnaLysis) global database with stable carbon and oxygen isotope time-series from 18 speleothems from 14 caves. The currently available oldest record from the studied region is the ABA-2 flowstone record (Abaliget Ca...
Conference Paper
Full-text available
Dawsonite is often mentioned as an indicator for CO2 infiltration in geological reservoirs. Stable isotope characteristics of carbonates in CO2-bearing fluid reservoirs can help us to better understand the chemical and physical processes, which control carbonate dissolution and precipitation during infiltration of CO2-rich fluids. In addition, stab...
Article
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Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercom...
Article
In addition to the collagen and phosphate components of bones and teeth, the stable carbon and oxygen isotope compositions of skeletal carbonate are frequently measured to determine diet, environmental conditions, and populational or individual migration in bioarchaeological research. A standardized method for the stable isotopic analysis of skelet...
Article
A stalagmitic flowstone deposit from the Béke Cave (called Nagy-tufa deposit), East-Central Europe is characterized by complex, climate related textural and geochemical records as documented from a drill core (BNT-2 core) covering the period of 4 to 1 ka cal BP. The core location was monitored in an earlier study. Based on monitoring, textural and...
Article
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Despite its thermodynamical metastability at near-surface conditions, aragonite is widespread in marine and terrestrial sediments. It abundantly forms in living organisms, and its abiotic formation is favored in waters of a Mg 2+ /Ca 2+ ratio > 1.5. Here, we provide crystallographic evidence of a nanocrystalline CaCO 3 polymorph, which precipitates...
Preprint
The region of Eastern Europe & Turkey contributed to the SISAL (Speleothem Isotopes Synthesis and AnaLysis) global database with stable carbon- and oxygen isotope time-series from 18 entities from 14 cave systems. The currently available oldest record from this region is the ABA-2 flowstone record (Abaliget Cave; Hungary) reaching back to MIS 6. Th...
Conference Paper
Full-text available
Carbon capture and storage have become a vital problem in the last decades because the concentration of carbon-dioxide is constantly increasing in the atmosphere in relation with anthropogenic emissions. To reach long-term safety of geological storage of CO2, we need to know the geological environment, its behavior, and the influence of the complex...
Conference Paper
Full-text available
Dawsonite is often mentioned as an indicator mineral for CO2 infiltration in geological reservoirs. The study of stable isotope characteristics of carbonates in CO2-bearing fluid reservoirs can help us to have better understanding in the chemical and physical processes, which control carbonate dissolution and precipitation mechanism during infiltra...
Article
Full-text available
Uneven spacing is a common feature of sedimentary paleoclimate records, in many cases causing difficulties in the application of classical statistical and time series methods. Although special statistical tools do exist to assess unevenly spaced data directly, the transformation of such data into a temporally equidistant time series which may then...
Article
Full-text available
In order to use speleothems in the reconstruction of past climate and environmental changes it is necessary to understand the environmental and hydrological processes that determine the physico-chemical conditions of carbonate precipitation and hence speleothem formation. Therefore, in this study an extended monitoring program was conducted in the...
Article
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Centennial-scale mineral dust peaks in last glacial Greenland ice cores match the timing of lowest Greenland temperatures, yet little is known of equivalent changes in dust-emitting regions, limiting our understanding of dust−climate interaction. Here, we present the most detailed and precise age model for European loess dust deposits to date, base...
Article
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Archaeological evidence points to substantial changes in Bronze Age societies in the European-Mediterranean region. Isotope geochemical proxies have been compiled to provide independent ancillary data to improve the paleoenvironmental history for the period of interest and support the interpretation of the archaeological observations. In addition t...
Article
Rationale: We have used ahigh-precision, high efficiency method for themeasurementof the(2) H/(1) H ratios of hydrous silicates (amphiboles) and nominally anhydrous minerals (NAM) such as clinopyroxene, garnet and diamond, which are usually extremely resistant to pyrolysis. This opens up new fields of investigation to better understand the conditi...
Article
This study introduces a novel approach intertwining analytics of spatial microbial distribution with chemical, mineralogical and (micro)structural related aspects in corroded concrete sewer environments. Samples containing up to 4cm thick corrosion layers were collected from concrete manholes and analysed using hydro-geochemical, microbiological, b...
Article
Full-text available
Uneven spacing is a common feature of sedimentary paleoclimate records, in many cases causing difficulties in the application of classical statistical and time series methods. Although special statistical tools do exist to assess unevenly spaced data directly, the transformation of such data to a temporarily equidistant time series applicable to co...
Conference Paper
Full-text available
A Szemlő-hegyi-barlang a rózsadombi barlangok magasabb topográfiai helyzetben található, jelenleg a termálvizes oldás szempontjából már inaktív tagja. Itt egy járatrendszeren belül tanulmányozhatóak a jellemzően hipogén és az azt módosító epigén karsztos folyamatok és hatásuk. A barlang főként a Szépvölgyi Mészkőben, egyes szakaszokon alárendelten...
Conference Paper
Full-text available
The efficient, safe and cost-effective collection and transport of sewage is a key criteria maintaining expected sanitary standards of modern society. Within the last century microbial induced concrete corrosion (MICC) has been recognized as one of the main processes for degradation of concrete based sewer networks worldwide, triggering high econom...
Article
Studies on the last interglacial (LIG) can provide information on how our environment behaved in a period of slightly higher global temperatures at about 125 ± 4 ka, even if it is not the best analogue for the Holocene. The available LIG climate proxy records are usually better preserved and can be studied at a higher resolution than those of the p...
Article
The Pliocene and Early Pleistocene (5.2–1 Ma) palaeoclimate for localities in Italy is evaluated using stable carbon and oxygen isotope compositions of tooth enamel of fossil specimens from Rhinocerotidae (Stephanorhinus sp.) and Gomphotheriidae (Anancus sp.) taxa. Carbon isotope composition was measured in the structural carbonate (δ¹³C), while ox...
Article
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Speleothem deposits are among the most valuable continental formations in paleoclimate research, as they can be dated using absolute dating methods, and they also provide valuable climate proxies. However, alteration processes such as post-depositional mineralogical transformations can significantly influence the paleoclimatic application of their...
Article
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This study is intended to clarify the depositional environment of a 180-m-thick, immature, limy Middle Miocene oil source rock interval, cored in the Zala Basin, western Hungary. For this purpose, a highly interdisciplinary approach was applied combining simple, standard micropaleontological, isotopic, and organic geochemical methods, rarely applie...
Article
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Exploitation of thermal water frequently entails the precipitation of various minerals (scaling) due to elevated salinity and gas contents in deep aquifers. Progressive clogging of wells, pumps, pipes, valves and heat exchangers can cause major problems in geothermal heat and electric power production. In this context scale deposits constitute an e...
Conference Paper
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Mineral precipitates (scaling) arising from thermal waters are widespread due to high dissolved solid and gas contents at elevated temperature and pressure in deep aquifers. Reduction of inner diameters or complete clogging of wells, downhole pumps, transport pipes and heat exchangers by carbonate, sulfate or silica minerals constitutes a major pro...
Article
Full-text available
In the Transdanubian Range (Hungary), dolostone and dolomitic limestone appear in a number of sedimentary successions formed from the Late Permian to the Late Triassic in various depositional settings and under various diagenetic conditions, whereas only a negligible amount of dolomite was detected in the post-Triassic formations. Seven dolomite-be...
Conference Paper
Full-text available
A 70 kyr long stalagmite record from southern Turkey since the last interglacial ABSTRACT Anatolia has a key role for paleoclimate research in eastern Mediterranean region. It is situated at the linkage area between North Atlantic-Alpine-Mediterranean cyclones and Arabian-Indian-Tibet monsoon climate models. Thus it is necessary to understand pal...